Endocrine Abstracts

Osteoporosis in children is not just BMD and bisphosphonates. Children are unique in their ability to grow and repair bone tissue. Diagnostics, management and the spectrum of osteoporotic conditions encountered in children are different from adults. Children can have primary osteoporosis which are rare diseases like osteogenesis imperfecta (OI), and secondary osteoporosis resulting from chronic conditions or their treatment. Disorders of the bone minerals calcium and phosphate, or their supplier vitamin D, can cause rickets and osteomalacia but are not a form of osteoporosis.

The revised ISCD paediatric position papers determine that paediatric osteoporosis is diagnosed by the combined presence of low size-corrected bone density and fractures, namely at least 1 vertebral or lower extremity long bone fracture, or at least 2 upper extremity long bone fractures. Commonly used size corrections for DXA involve calculating the volumetric density (BMAD, g/cm³) for lumbar spine scans or removing the skull for total body scans (total body less head). Assessing musculoskeletal health overall and interpreting density results requires skill and a profound understanding of growth, bone geometry and biomechanics.

Management of paediatric osteoporosis differs according to the underlying condition, and between major treatment centres. Most experience still derives from treatment of OI, but more evidence is now emerging on secondary osteoporosis. In OI, bisphosphonate therapy can reshape broken vertebrae, increase cortical thickness and bone mass, and reduce fracture risk and pain. Questions remain on when to stop drug therapy. Apart from bisphosphonates, other new anti-resorptive drugs are now being trialled in children. Non-drug treatments such as whole body vibration therapy are also studied to assess whether muscle strengthening can influence bone.

A successful team for managing paediatric bone disorders includes physiotherapy, occupational therapy, orthopaedic surgery and expertise in DXA interpretation, and should be in the hands of a paediatrician experienced in bone disease.